This invention relates to nitride layer, including metal nitride layer, forming methods and diffusion barrier forming methods, including diffusion barriers for integrated circuit wiring.
Several advantages exist to replacing aluminum with copper as the preferred metallization in semiconductor devices. The higher conductivity of copper allows reduction in the cross-sectional area of conductive components and/or an increase in electric current. However, several disadvantages of copper metallization exist as well. One such disadvantage is that diffusion barriers are more frequently desired to prevent diffusion of copper into surrounding materials. Conventional diffusion barriers for copper metallization are typically formed in an awkward, somewhat inefficient process. Accordingly, a need exists to form diffusion barriers for copper metallization in a simple yet effective manner.
One aspect of the invention includes a nitride layer forming method wherein a material is electrodeposited on a substrate and converted, at least in part, to a layer comprising nitrogen and the electrodeposited material. By way of example, the electrodepositing may occur substantially selective on a conductive portion of the substrate. Also, the converting may comprise exposing the electrodeposited material to a nitrogen-comprising plasma. Chromium nitride and chromium oxynitride are examples of nitrogen-comprising materials. Copper or gold wiring of an integrated circuit are examples of a substrate. The processing temperature during the electrodepositing and the converting may be selected not to exceed 500xc2x0 C.
In another aspect of the invention, an integrated circuit wiring forming method includes forming an outer portion of patterned integrated circuit wiring over a substrate by a process other than sputter deposition. The method further includes nitridizing the outer portion with a nitrogen-comprising plasma to form a nitride layer on the wiring. The thickness and composition of the nitride layer may be effective to limit diffusion of at least one component of the wiring through the nitride layer.
In yet another aspect, a method of forming a material comprising a metal nitride may include electrodepositing a metal-containing material on a conductive surface. The metal-containing material may be exposed to a nitrogen-comprising environment and at least some of the metal-containing material may be transformed to a metal nitride.
In a still further aspect, a diffusion barrier forming method may include forming a patterned layer of integrated circuit copper or gold wiring over a substrate. The wiring may be exposed to a chromium-ion-comprising environment while applying an electric current to the wiring to deposit chromium on the wiring. The chromium may be converted to a chromium-nitride-comprising diffusion barrier using a nitrogen-comprising plasma.